#include<iostream>
#include<string>

using namespace std;

int main()
{
  string s1("hello world");
  cout << s1 << endl;
  
  string::iterator it = s1.begin();
  while (it != s1.end())
  {
    (*it)++;
    it++;
  }
  
  cout << s1 << endl;

  return 0;
}
